| Due to the excellent structure and properties,TiO2 semiconductor was considered as one of the most promising materials in the many new materials,and it was widely applied in the fields such as catalysis and new energy.As the catalytic material,TiO2 was seriously limited for its low quantum efficiency.Mesocrystal is a unique ordered superstructure assembled with a large number of oriented nanoparticles,which shows distinct characteristics of high crystalline,high porosity and single-crystal-like structure,and it could effectively improve the properties of TiO2 semiconductor.Therefore,the related research of TiO2 mesocrystals is of great significance.In recent years,TiO2 mesocrystals have attracted more and more attention,however,there are lots of challenges to prepare TiO2 mesocrystals simply,and its growth mechanism remained unknown.Herein,we developed a new synthesis strategy to get a novel dumbbell-shape anatase TiO2mesocrystals firstly.In addition,the modification research was carried out,and it was applied as a high-efficiency photocatalytic material.This main research content is as follows:1)A new strategy was explored to synthesize a novel dumbbell-shape anatase TiO2mesocrystals with glacial acetic acid served as solvent and TiCl3 served as the Ti source.Using a series of characterization and analysis,we deeply researched the structures and properties of this nanomaterials.What’s more,the growth mechanism of the dumbbell-shape TiO2 mesocrystals was probed.Besides,plenty of oxygen vacancy was introduced to the dumbbell-shape TiO2 mesocrystals by using a simple vacuum heat treatment.Subsequently,this nanomaterials were applied as photocatalyst to study the performance of photocatalytic reduction for Cr（VI）and photocatalytic oxidation for MO.The experimental results manifested that the TiO2 mesocrystals showed more excellent performance than the conventional TiO2 single crystal nanoparticles.Moreover we researched and analyzed the photocatalytic reaction mechanism of this TiO2 mesocrystals materials.2)Based on the previous research,we did an extension research of the dumbbell-shape TiO2 mesocrystals that graphene nanosheets and TiO2 mesocrystals were combined to form the heterojunction structure by a simple hydrothermal reaction.A series of characterization and measurements have been taken to analyze the structures and properties of the composite.Consequently,it is verified that the GO and TiO2 were combined together by chemical bonds which can effectively improve the carriers separation and migration,inhibit the recombination of electrons and holes.The composite of GO and TiO2 mesocrystal significantly improved the photocatalytic performance.Under 100 mW/cm2 simulated sunlight（with AM 1.5G filter）,the composite revealed efficient performance of photocatalytic oxidation for MO.and reduction for Cr（VI）,and the photocatalytic mechanism have been discussed. |
